1. Field of the Invention
The present invention relates generally to monitoring systems for monitoring assets, objects, people and animals and associated methods and, more particularly, to asset, object, people and animal monitoring systems and associated methods for monitoring the location and/or status of assets, objects, people and animals.
2. Related Art
Monitoring the status and location of assets, objects, people or animals is a vital part of everyday life. Improving the methodologies for doing this improves in countless ways the lives of everyone. Because of the large number of variables involved with monitoring assets, objects, people or animals, the background of one example embodiment will be described in detail.
Each day, large quantities of freight which has a cumulative value of many millions of dollars are shipped throughout the United States and throughout the world. For example, large quantities of freight are loaded into rail cars and shipped by railroad. Likewise, large quantities of freight are stored in shipping structures and shipped by ship or barge. Even larger quantities of freight are commonly loaded into trailers and shipped by truck.
Due to the quantity and the value of the freight, the owner of the freight as well as the shipper who has assumed custodial responsibility for the freight would like to monitor the position or location of the freight, regardless of its mode of transportation. Moreover, the owner of the freight as well as the shipper would often times also like to monitor the status of the freight while the freight is in route. Monitoring the status of the entire structure in which the freight lies is well known in the art and is described in U.S. Pat. No. 5,917,433 entitled Asset Monitoring System and Associated Method. That patent enables, for example, monitoring the temperature of a refrigerated trailer in transport to insure that the refrigerated products stored within the trailer are appropriately chilled. However, due to power limitations of the current state of the art as well as multipath problems of having a plurality of radio transmitters transmitting within a structure, the ability to monitor individual objects within a structure has been unachieved.
The earliest method of monitoring the progress of a tractor-trailer required the driver to periodically park the tractor and inspect the contents of the trailer and to telephone the central station or dispatcher in order to report the present location of the tractor-trailer and to obtain updated delivery information and status of the cargo. By requiring the driver to periodically telephone the central station or dispatcher, however, the average speed of the tractor-trailer was significantly reduced. In addition, the information relating to the present location of the tractor-trailer provided by the drivers was sometimes inaccurate, due either to inadvertent mistakes or attempts by the driver to intentionally mislead the dispatcher regarding the progress of the tractor-trailer.
As a result, more sophisticated monitoring systems have been developed which allow communications to be established between the driver of a tractor and a central station or dispatcher, while the tractor-trailer continues along its route. These monitoring systems can also include a receiver mounted to the tractor for communicating with the Global Positioning System (GPS) satellites in order to determine the present location of the tractor-trailer. The monitoring systems can then transmit information relating to the present position of the tractor-trailer to the central station or dispatcher without requiring the driver to stop the tractor-trailer and to telephone the central station or dispatcher.
Conventional monitoring systems can also include one or more sensors for monitoring predetermined engine parameters, such as the oil pressure or engine temperature. Data representing these parameters can then be transmitted to the central station or dispatcher on an event-triggered, i.e., emergency basis, on a regularly scheduled basis or as requested or polled. In addition, conventional monitoring systems can include one or more sensors mounted within or upon the trailer in order to monitor predetermined conditions within the trailer, such as the temperature within a refrigerated trailer. This is not problematic with conventional radios if a single sensor is monitoring and transmitting information on single criteria, for example temperature. However, if there are a number of different criteria to be monitored on individual cargo items, for the reasons subsequently articulated, conventional wireless transmission are inadequate.
In a like fashion, these tractor-based monitoring systems can then transmit the sensory signals provided by the trailer sensors to the central station or dispatcher. Accordingly, conventional monitoring systems can monitor the location of the tractor, while monitoring a very limited number of predetermined engine or trailer conditions as the tractor-trailer continues along its route.
As has been discussed, a variety of monitoring systems have been developed which are designed to monitor the location and, in some instances, the status of freight during shipment. However, all of these prior systems have in some way relied on conventional radio and communication systems with the concomitant limitations.
For example, conventional radio systems are band and power limited. Further, they are subject to multipath effects and perform poorly in many environments. Because of these aforementioned limitations conventional monitoring systems typically only monitor large structures such as tractor trailers or shipping cargo trailers. Multi-path effects and limited bandwidth prevent placing asset monitoring transmitters within the shipping structures themselves.
The prior system limitations can be exemplified. A tractor trailer may be shipping very valuable cargo across the country and it is desired to monitor the location and status of the cargo. The cargo may be biohazardous material that must be maintained at a certain temperature. With current systems, only the overall temperature and position of the trailer can be ascertained. If an individual canister is removed or if its individual temperature exceeds a predetermined limit, it could not be determined. Consequently, there has been a persistent need in the asset monitoring industry to not only track and monitor the status of a structure as a whole, but also to track and monitor individual assets, objects, people or animals within that structure.